1. Field of the Invention
The present invention relates to magnetic tape read/write heads, and more specifically, to selectively activate data channels in a tape drive to optimize data throughput.
2. Background of the Invention
Magnetic tape is a widely used sequential storage medium used for data collection, backup, and historical purposes. Magnetic tape is made of flexible plastic with one side coated with a ferromagnetic material. Tape drives and their corresponding tape media are applied to data storage tasks in all levels of computer data storage from personal computers to workstations to mainframes and supercomputers. Much of magnetic tape's popularity is due to the fact that tape offers the lowest cost per unit of storage and highest volumetric storage efficiency of all available technologies. Tape products are available in many formats from many vendors in a wide range of cost categories.
For information storage and retrieval, magnetic tape has proven especially reliable, cost efficient, and easy to use. In order to make magnetic tape even more useful and cost effective, emphasis has been placed on developing high speed data transfer methods for future tape drives. Many of the newer tape drives can read and write data at very high data transmission rates, which enhances their efficiency with systems and applications that need this capability. However, not all computers/networks or applications can match the data transfer rates generated by this new generation of tape drives. The vast majority of these existing slower-capability infrastructures will still be in use due to the high cost of replacement. Thus, these infrastructures are not necessarily capable of supporting the high data transfer rates from the tape drives under development.
Traditionally, managing problems associated with interfacing a high-speed tape drive to an infrastructure that cannot support the high-speed data transfer rates include using a variable speed control in the tape drive to match the tape drive throughput to the interface. However, there are drawbacks to using this approach, including complicating the speed control and the clock for reading and writing data, as well as being limited by how slow the throughput speed can be set and still maintain proper tape tension and fly height control. Another approach to handle the variance in the drive's transfer rates and the capabilities of the infrastructure is to stop the tape drive when the interface cannot keep up with the tape drive, backup the tape, and then resume the data transfer. However, the data transfer may still overwhelm many of the networks to which the tape drive is attached. This situation can result in continuous stop, backup, and resume operations. Such operations can cause excessive wear on both the tape drive and medium.
Therefore, it would be advantageous to have an improved method and apparatus for optimizing the throughput of a tape drive that overcomes the drawbacks of the prior art.